There is an ancient expression that goes something like this: "If Candlemas be bright and clear, there'll be two winters in the year."
Many of the ancient cultures believed that certain weather conditions at one time of the year could affect weather conditions at another. They also believed that certain animals had magical abilities. The ancient Egyptians, for example, believed that cats could protect their homes. The ancient Celts believed that groundhogs could predict the weather. There is no truth in this. It's just an old myth. But it's a delightful old myth.
In modern times, people pulled out this old superstition believed by the ancient Celts and created Groundhog Day!